High aperture objective of the extended gauss-type



Dec. 12, 1967 J. BECKER 3,357,776

HIGH APERTURE OBJECTIVE OF THE EXTENDED GAUSS-TYPE Filed Nov. 21, 1965 fie. 6 55. 7 5's. 0

2 BY, v/

ATTORN EYS SEARCH R00 United States Patent 3,357,776 HIGH APERTURE OBJECTIVE OF THE EXTENDED GAUSS-TYPE Johannes Becker, Delft, Netherlands, assignor to N.V. Optische Industrie De Oude Delft, Delft, Netherlands Filed Nov. 21, 1963, Ser. No. 325,335 Claims priority, application Netherlands, Nov. 30, 1962,

2 Claims. 01350-210 The invention relates to a high aperture objective of the extended Gauss-type which consists of seven single lenses forming five components, of which components, taken in the order from the long towards the short conjugate side of the objective, the first and second each consist of a single meniscus lens (L L of positive power turning its concave side towards the diaphragm; the third is a negative meniscus component positioned on the same side of the diaphragm as the first and second components with its concave side turned towards the diaphragm, and consists of a biconvex lens (L and a biconcave lens (L the fourth is a meniscus of weak power positioned on the opposite side of the diaphragm with its concave side turned towards the diaphragm and consists of a biconcave lens (L and a biconvex lens (L and the fifth is a single biconvex lens (L Objectives of this type having a relative aperture up to f/ 1.2 and an angular field 2w of 40 have been described in the United States patent specification 2,836,102.

My invention has for its principal object to provide an objective of the type referred to yielding a still higher aperture while maintaining a good state of correction in a flat field of approximately 40.

In accordance with my invention, this can be achieved by observing a number of conditions in combination as follows:

n1 1.7 n l.72 I n l.72 n 1.7 "1 "2 '1 H 1.2I3 I'4 1.75I'3 0.3 n n 0.l5 III |"12l 11 |"12| IV in which Lsubsmpt designates the lenses and nsubsmpt is the refractive index for the d-line of the spectrum of the lenses in the order indicated above, going from the first to the fifth component, and rsubscrm is the radius of curvature of the lens surfaces, likewise taken in the order indicated. 1

The conditions indicated by I and II, while allowing to increase considerably the relative aperture of the objective, appear to be especially effective for the correction of astigmatism in a fiat field whereas the conditions referred to by III and IV have a particularly favorable infiuence on the correction of coma.

In the accompanying drawing:

FIG. 1 and FIG. 2 show two examples of objectives in accordance with my invention;

FIGS. 3-5 show aberration curves of the objective according to FIG. 1; and

FIGS. 6-8 show aberration curves of the objective according to FIG. 2.

The data of the examples illustrated in FIGS. 1 and 2 are given in the following Tables I and II, respectively. Herein nsubscflpt and rsubsmpt have the same meaning as indicated above; dsubsmpt is the axial thickness of, or the axial distance between the lenses, and vsubmm is the Abbe number of the lens materials, the subscripts in all cases increasing from the first to the fifth component.

3,357,776 Patented Dec. 12, 1967 v we Ra'lius 0t LJIS Refractive Abbe Curvatuxe, r Thickness or In lex, ns Number, u

Distance, 11

Tl 111. 5 L1 350 6 d 9.515 m=L 7201 m=50.3

(11 0. l. r: 65. 7 L2 104 1 d3 8. 545 71-2=1. 7342 va=51. 0

- d4 0.97 r, 53.4 L3 3 9 I (is =22. 8 n.-;=1. 6422 u =58. 1

r5 L4 98 0 dg 4. 175 m=1.7184 v4=29.5

44 4 (l1 =22. 235 8 L 8 d 1.8 ns=1. 5481 v =45.9

ra La c- 75 4 d 11. 36 7I5=L 7440 v5=44. 9

1o= 0 1 ru= 150. 4 L7 106 5 dn= 7. 96 n1=1. 7342 w7=5l..0

TABLE II (FIG. 2) [F=100; 170.95; 2w=401 Radius of Lens Thiek- Refractive Curvature, ness or index, Abbe number,

r Distinct), n 11 T1 136. 1 L1 489 9 d =10.175 7Z1=1. 7550 v1=53. 3

dz 0.2 7': 69.8 L3. 6 d 9. 31 Tl2=1. 7885 ug=50.45

58 1 d4 0.93 r In. 15 7 d =26.13 7ls=1. 6516 v =58.5

o L4... 29 8 (is 4.12 7l4=1. 7215 1q=29.3

d =24. 6 rs 41. 1 L5 92 0 d5 1. 73 7l5=1. 5235 v5=50.9

o L9. 71 4 d9 =10. 57 TLB=L 7440 va=44. 9

l d u= 0. 2 T1 136. 3 L 105 6 d11= 8.24 n1=1.7550 v1=53.3

In the tables and in FIGS. 1 and 2 the lenses are identified by L L the diaphragm by D.

The FIGS. 3, 4 and 5 illustrate in the usual manner the aberrations of the objective of FIG. 1 for the d-line of the spectrum, more particularly the spherical aberration and the unsatisfied amount of sine condition, the astigmatism and the distortion, respectively. In a similar way the FIGS. 6, 7 and 8 show the corresponding aberrations of the objective according to FIG. 2.

I claim:

1. A high aperture objective of the extended Gausstype having a relative aperture greater than 1/ 1.2 and a field angle of substantially 40, which consists of seven single lenses forming five components, of which components, taken in the order from the long towards the short conjugate side of the objective, the first and second each consist of a single meniscus lens (L L of positive power turning its concave side towards the diaphragm; the third is a negative meniscus component positioned on the same side of the diaphragm as the first and second components with its concave side turned towards the diaphragm, and consists of a biconvex lens (L and a biconcave lens (L the fourth is a meniscus of weak power positioned on the opposite side of the diaphragm with its concave side turned towards the diaphragm and consists of a bi- Radius of Lens Refractive Abbe Curvature, r Thickness or Index, na Number, v

Distance, :1

T1 111. 5 L d 9. 515 m=1. 7201 v1=59. 3

d1 0. 1 T3 65. 7 I4 dz 8. 545 7ls=1. 7342 =51.

d =22.8 m=1.6422 va=58.1 o 329. 1 L4 d5 4.175 m=1. 7184 v4=29. 5

d1 =22. 235- r; 44. 4 L d 1. 8 'n =1. 5481 v5=45. 9

9 80.8 Lg (1,; =11. 36 na=1.7440 v =44.9

dio= 0. 1 m 150. 4 L d 7.96 n:=1.7342 1q=51.0 m= l06. 5

' conjugate side of the objective.

2. A high aperture objective of the extended Gauss-type having a relative aperture greater than 1/ 1.2 and a field angle of substantially 40, which consists of seven single lenses forming five components, of which components, taken in the order from the long towards the short conjugate side of the objective, the first and second each consist of a single meniscus lens (L L of positive power turning its concave side towards the diaphragm; the third is a negative meniscus component positioned on the same side of the diaphragm as the first and second components with its concave side turned towards the diaphragm, and

4 consists of a biconvex lens (L and a biconcave lens (L the fourth is a meniscus of weak power positioned on the opposite side of the diaphragm with its concave side turned towards the diaphragm and consists of a biconcave lens (L and a biconvex lens (L and the fifth 1s a single biconvex lens (L which ob ective fulfills the following conditions:

Radius oi Lens Thlek- Refractive Abbe Curvature, r ness or index, n number, 1!

Distance, d

n 136. 1 L1 d1 =10. m=1. 7550 1q==53. 3

d7 0. 2 r; 69.8 L: d 9. 31 m=l. 7885 vz=50. 45

d4 0. 93 f5 58. 1 L; (1; =26. 13 1L3=1- 6516 va=58. 5

(in 4.12 n =1. 7215 v4=29. 3 r 29. 8

d1 =24. 6 T5 41. 1 5 d: l. 73 m=1. 5235 u5=50. 9

T9 92. 0 s..- lie =10. 57 7le=1. 7440 va -44. 9

dm= 0. 2 T11= 136. 1. L7 du= 8. 24 n1=1. 7550 v1=53.3

wherein Lsubsmpt designates the lenses, [subscript the radius of curvature of the lens surfaces, d the lens thickness or the distance between lenses along the optical axis, nsnbsmpt the refractive index for the d-line of the spectrum of the lenses, and vsubsmpt the Abbe-number of the lenses, all subscripts increasing from the long towards the short conjugate side of the objective.

References Cited UNITED STATES PATENTS 2,811,082 10/1957 Werfeli 88-57 2,836,102 5/1958 Ito 8857 JEWELL H. PEDERSEN, Primary Examiner. J. K. CORBIN, Assistant Examiner. 

1. A HIGH APERTURE OBJECTIVE OF THE EXTENDED GAUSSTYPE HAVING A RELATIVE APERTURE GREATER THAN 1/1.2 AND A FIELD ANGLE OF SUBSTANTIALLY 40*, WHICH CONSISTS OF SEVEN SINGLE LENSES FORMING FIVE COMPONENTS, OF WHICH COMPONENTS, TAKEN IN THE ORDER FROM THE LONG TOWARDS THE SHORT CONJUGATE SIDE OF THE OBJECTIVE, THE FIRST AND SECOND EACH CONSIST OF A SINGLE MENISCUS LENS (L1, L2) OF POSITIVE POWER TURNING ITS CONCAVE SIDE TOWARDS THE DIAPHRAGM; THE THIRD IS A NEGATIVE MENISCUS COMPONENT POSITIONED ON THE SAME SIDE OF THE DIAPHRAGM AS THE FIRST AND SECOND COMPONENTS WITH ITS CONCAVE SIDE TURNED TOWARDS THE DIAPHRAGM, AND CONSISTS OF A BICONVEX LENS (L2) AND A BICONCAVE LENS (L4); THE FOURTH IS A MENISCUS OF WEAK POWER POSITIONED ON THE OPPOSITE SIDE OF THE DIAPHRAGM WITH ITS CONCAVE SIDE TURNED TOWARDS THE DIAPHRAGM AND CONSISTS OF A BICONCAVE LENS (L5) AND A BICONVEX LENS (L6); AND THE FIFTH IS A SINGLE BICONVEX LENS (L7), WHICH OBJECTIVE FULFILLS THE FOLLOWING CONDITIONS: 